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As the rise in pore water pressure is one of the main factors in triggering landslides, the understanding of groundwater processes taking place at the hillslope scale is a crucial issue in slope stability analysis. However, identifying flow-paths travelled by water molecules from their infiltration is still a complex task. Hydrochemistry is recognized as a powerful tool that can help to gain useful hydrogeological information and has gradually become increasingly used in addition to conventional study methods. This manuscript presents a comprehensive geochemical investigation consisting of leaching tests and quantitative mineralogical analyses on soil samples, chemical analyses on groundwater samples and modelling. Our results highlighted the usefulness of coupling, even in hydrogeological studies focusing on landslides, geochemical surveys on both water and the soil matrix to constrain the interactions between host-rocks and groundwater. Moreover, it demonstrated that kinetic-based geochemical models, if properly calibrated on leaching tests, can provide valuable information on groundwater dynamics, allowing us to elucidate water-mixing processes beneath the soil surface.

This Editorial paper sums up the contents of the Special Issue named “Applying Artificial and Environmental Tracing Techniques in Hydrogeology” [...]

Climate change affects areas worldwide by modifying their hydrological cycle. In the Mediterranean area, the water resources are experiencing an overall decrease in water quantity together with a worsening of their quality because of climate change. Emilia-Romagna region is one of the Italian regions with the highest water demand due to agricultural and industrial activities. There, quantification of water availability (WA: the proportion of precipitation available at the soil surface for subsequent infiltration and runoff processes) can no longer be postponed. Thus the monthly actual evapotranspiration (AET0m) was calculated using a simply downscaling Budyko approach. The method was applied to 100 controlled and homogeneous meteorological stations, located in the Emilia-Romagna region in the north of Italy. The datasets were divided into two subperiods, from 1961 to 1990 and 1991 to 2015, in which the monthly AET0 and WA were calculated. This information is needed by stakeholders in charge of groundwater management for further adaptation plans, such as managed recharge and the development of agricultural best practices able to induce an increase in groundwater levels and water quality. To assess the variation of water resources in the Emilia-Romagna region, we have downscaled the formula of annual AET0 established by Budyko to the monthly scale. Further, the monthly WA was computed at high spatial resolution. The climate data of monthly minimum and maximum temperatures and monthly precipitations over 1961–2015 from 100 weather stations were used. Results show a remarkable reduction of WA (about 10%) in the whole region, with the exception of the northeastern part of the Emilia-Romagna region. The decrease in the mean annual WA is more focused in the winter months (about 83 mm) and mainly affects the mountainous areas. This study lays the foundations to rethink and improve the management of water resources in the area.

We compared five regression approaches, namely, ordinary least squares, major axis, reduced major axis, robust, and Prais–Winsten to estimate δ18O–δ2H relationships in four water types (precipitation, surface water, groundwater collected in wells from lowlands, and groundwater from low-yield springs) from the northern Italian Apennines. Differences in terms of slopes and intercepts of the different regressions were quantified and investigated by means of univariate, bivariate, and multivariate statistical analyses. We found that magnitudes of such differences were significant for water types surface water and groundwater (both in the case of wells and springs), and were related to robustness of regressions (i.e., standard deviations of the estimates and sensitiveness to outliers). With reference to surface water, we found the young water fraction was significant in inducing changes of slopes and intercepts, leading us to suppose a certain role of kinetic fractionation processes as well (i.e., modification of former water isotopes from both snow cover in the upper part of the catchments and precipitation linked to pre-infiltrative evaporation and evapotranspiration processes). As final remarks, due to the usefulness of δ18O–δ2H relationships in hydrological and hydrogeological studies, we provide some recommendations that should be followed when assessing the abovementioned water types from the northern Italian Apennines.

This study sums up the first estimates of the young water fraction (Fyw; here understood as the percentage proportion of groundwater passing through the well’s screen and younger than approximately 2–3 months) from groundwater collected in 75 wells from alluvial fans facing the northern Italian Apennines of Italy. The Fyw estimates were based on a monthly dataset of water-stable isotopes (oxygen-18 (18O)) from surficial water (9 rivers), while the dataset of groundwater (75 wells) consisted of three-monthly isotopic data. In the cases of surficial water and stable isotopes, these lasted over the period of January 2003 to December 2007, while in the case of groundwater, the data were collected from January 2005 to December 2007. The values of Fyw were estimated by means of a sine-wave fitting technique; the results made evident the presence of unexpectedly reduced differences between groundwater. In particular, shallower groundwater hosted in aquifers from the apical parts of the alluvial fans (i.e., aquifers characterized by the coarsest materials such as gravels and sands, and closest to the recharge areas) showed similar values of Fyw to the deepest aquifers from the distal parts; however, former studies mentioned here evidenced the existence of poorly recharged old groundwater. Our results seem to confirm a complex behavior of these aquifers compared with what had previously been thought.

Deep-seated landslides are complex systems. In many cases, multidisciplinary studies are necessary to unravel the key hydrological features that can influence their evolution in space and time. The deep-seated Berceto landslide, in the northern Apennines of Italy, has been investigated in order to define the origin and geochemical evolution of groundwater (GW), to identify the slope system hydrological boundary, and to highlight the GW flow paths, transit time and transfer modalities inside the landslide body. This research is based on a multidisciplinary approach that involves monitoring GW levels, obtaining analyses of water chemistry and stable and unstable isotopes (δ18O-δ2H, 3H, 87Sr/86Sr), performing soil leaching tests, geochemical modelling (PHREEQC), and principal component analysis (PCA). The results of δ18O-δ2H and 87Sr/86Sr analyses show that the source of GW recharge in the Berceto landslide is local rainwater, and external contributions from a local stream can be excluded. In the landslide body, two GW hydrotypes (Ca-HCO3 and Na-HCO3) are identified, and the results of PHREEQC and PCA confirm that the chemical features of the GW depend on water–rock interaction processes occurring inside the landslide. The 3H content suggests a recent origin for GW and appears to highlight mixing between shallow and deep GW aliquots. The 3H content and GW levels data confirm that shallow GW is mainly controlled by a mass transfer mechanism. The 3H analyses with GW levels also indicate that only deep GW is controlled by a pressure transfer mechanism, and this mechanism is likely the main influence on the landslide kinematics.

The mechanisms controlling the onset of minor slope instability at the edges of rocky plateaux exhibiting lateral spreading phenomena are yet to be fully understood. Hypotheses have recently been introduced to explain the influence of groundwater within these plateaux on geomorphological processes leading to slope instability. We present a back analysis of a recent landslide which occurred on 27th February 2014 in the town of San Leo, Italy. The role of the softening of basal clay shales and erosion due to seepage is investigated using finite element geomechanical models. Both processes were observed in the field and are related to groundwater discharging along the contact between the rocky slab and the clay-rich substratum. Fracture propagation paths involving pre-existing discontinuities and intact rock bridges failure were simulated using a simplified discrete fracture network (DFN) model coupled with a Voronoi polygonal mesh approach. Model results allow the failure to be classified as a secondary toppling phenomenon. Moreover, a critical amount of undermining was indicated by the models agreeing with field observations made prior to the failure. Based on the modelling results, an interpretation of the overall mechanism inducing failures at the edges of fractured rock slabs is given. In particular, the inter-relationships between groundwater flow and geomorphic processes acting within the rock masses are presented.

Understanding water infiltration and transfer in soft-clay shales slopes is an important scientific issue, especially for landsliding. Geochemical investigations are carried out at the Super-Sauze and Draix-Laval landslides, both developed in the Callovo-Oxfordian black marls, with the objective to define the origin of the groundwater. In situ investigations, soil leaching experiments and geochemical modeling are combined to identify the boundaries of the hydrological systems. At Super-Sauze, the observations indicate that an external water flow occurs in the upper part of the landslide at the contact between the weathered black marls and the overlying formations, or at the landslide basement through a fault network. Such external origin of water is not observed at the local scale of the Draix-Laval landslide but is detected at the catchment scale with the influence of deep waters in the streamwater quality of low river flows. Hydrogeological conceptual models are proposed emphasizing the role of the interactions between local (slope) and regional (catchment) flow systems. The observations suggest that this situation is a common case in the Alpine area. Expected consequences of the regional flows on slope stability are discussed in term of rise of pore water pressures and physicochemical weathering of the clay shales.

In the eastern Italian Alps, a large deep-seated rock block slide affects the S. Lorenzo road tunnel (46°23'49" N, 12°42'51" E) along the National Road 52 "Carnica", near to Passo della Morte (Udine Province); the tunnel was excavated through a fractured carbonatic rock mass overthrusted on clay-rich units. Previous studies of the unstable slope outlined the relationship between slope displacements and groundwater flow in the fractured rock mass. The conceptual geological model of the area, together with field observations, allowed specific investigation and monitoring activities to be defined in order to investigate this relationship. In particular, during the last years, six weirs were built and pressure transducers were installed in order to assess the total water discharge from the area. Moreover, 14 piezometers were drilled outside and inside the tunnel to monitor the hydraulic head. After 15 years of monitoring the groundwater system can be described in detail. In particular, results show a double flow system. The first is almost constant for all the year, while the second is influenced by rainfall events and is hosted in faults, fractures and joints in the western part of the tunnel, in the area of the larger and deep-seated rock slide. A three-dimensional groundwater flow model was built and calibrated along the total outflow from the road tunnel in order to better understand the interactions between groundwater flow and road infrastructure. In particular, the effects of countermeasures works, like the extension of the drainage adit in the carbonatic rock mass, was tested.

Nowadays, climate changes and increased water demand for human and agricultural purposes pose important questions for the groundwater management of alluvial aquifers facing the northern Italian Apennines. The large groundwater withdrawals, coupled with an overall worsening of the water quality, requires a detailed knowledge of the recharge mechanisms of these aquifers that can be useful for further adaptation measures. Concerning the recharge area of the alluvial aquifers (i.e., apices made up of gravelly materials), the present study investigates a dataset made up of 282 water samples for which stable isotopes oxygen-18 (18O) and deuterium (2H) are available. The latter involves precipitations (three rain gauges), surface water (five rivers) and groundwater (twenty wells) from five selected alluvial fans. The study confirms that the different isotopic signatures characterizing rain and river water from this area can be exploited for preliminary characterization of their significance on groundwater recharge. These results lay the foundations for the further use of a suite of environmental tracers (in which a primary role is that of water stable isotopes) at the event-scale (i.e., that of rainfall and/or flood) for eventually estimating the effective quota of recharge linked to precipitation and surface water.

Several prior studies investigated the use of stable isotopes of water in hydrogeological applications, most on a local scale and often involving the isotopic gradient (evaluated by exploiting the so-called altitude effect), calculated on the basis of rainwater isotopes. A few times, this gradient has been obtained using the stable isotopic contents of low-yield springs in a limited time series. Despite the fact that this method has been recognized by the hydrogeological community, marked differences have been observed with respect to the mean stable isotopes content of groundwater and rainwater. The present investigation compares the stable isotopic signatures of 23 low-yield springs discharging along two transects from the Tyrrhenian sea to the Po Plain of Italy, evaluates the different isotopic gradients and assesses their distribution in relation to some climatic and topographic conditions. Stable isotopes of water show that groundwater in the study area is recharged by precipitation and that the precipitation regime in the eastern portion of the study area is strongly controlled by a shadow effect caused by the Alps chain on the air masses from central Europe. Stable isotopes (in particular the &delta, 18O and deuterium excess (d-excess) contents together with the obtained isotopic gradients) allow us to identify in the study area an opposite oriented orographic effect and a different provenance of the air masses. When the windward slope is located on the Tyrrhenian side, the precipitation shows a predominant oceanic origin, when the windward slope moves to the Adriatic side, the precipitation is characterized by a continental origin. The main results of this study confirm the usefulness of low-yield springs and the need for a highly detailed survey-scale hydrological investigation in the mountainous context.

Slope instability phenomena frequently develop within clay-shales. Despite rise in pore-water pressures is one of the main factors for landslides triggering, hydrogeological processes taking place in slopes composed by clay-shales are far to be fully understood. That is due to the high heterogeneity of the materials and to the presence of fissures and fractures that can: (1) allow the presence of perched aquifers, (2) lead to the hydrogeological parting between stable and unstable sectors of the slope, (3) permit the development of preferential flow-paths. Moreover, (4) thrusts and faults can drive groundwater flow from far away, adding further complexity to the definition of the hydrogeological boundaries of the studied systems. Hydrochemistry is a powerful tool, which helps to unravel the abovementioned points. The purpose of this short note is to test the usefulness of geochemical modelling in identifying groundwater dynamics and interactions between host-rocks and groundwater. Both thermodynamic and kinetic approaches have been used in an earth-flow located in the northern Apennines of Italy.

Il presente lavoro riguarda la modellazione idrogeologica di un acquifero ospitato nella placca calcarenitica di San Leo (Appennino settentrionale). Quest'ultima e caratterizzata da un elevato grado di fratturazione che, associato alla permeabilita trascurabile del sottostante substrato argilloso, permette la formazione di un acquifero che alimenta alcune sorgenti presenti nell'area. La presenza della falda acquifera e l'evidente variabilita della sua superficie piezometrica nell'arco dell'anno idrologico possono influenzare la stabilita dei versanti.Il modello idrogeologico e stato sviluppato con un codice agli elementi finiti (FEFLOW, Wasy), considerando la placca come un mezzo poroso equivalente (Equivalent Porous Medium - EPM). I valori dei coefficienti di permeabilita e immagazzinamento per l'intero ammasso roccioso sono stati inizialmente ottenuti da rilievi geomeccanici. Inoltre, e stato effettuato, durante un periodo di magra nell'estate 2013, un rilievo di dettaglio delle sorgenti perenni che affiorano in prossimita del contatto tra le formazioni geologiche affioranti. Basandosi sui risultati di rilievi geomeccanici condotti sia con metodo tradizionale che analizzando i rilievi da laser scanner terrestre (Terrestrial Laser Scanner TLS), la permeabilita e stata considerata anisotropa. Il modello, calibrato con la localizzazione delle sorgenti perenni, e stato in seguito utilizzato per simulare la variazione della superficie piezometrica prima dell'evento franoso che ha interessato il lato nord-orientale della placca il 27 febbraio 2014.

Water resources are facing nowadays with two main problems: climate change and land cover variation. Their influences on environment and water resources have been evidenced worldwide. In this work, we have applied a complex methodology based on Geographical Information System (GIS) to combine the spatial information of several parameters that allow to obtain the groundwater vulnerability under climate and land cover modifications. The spatial analysis performed in this paper includes the aquifers, water availability, load pollution index, and infiltration map raster grids data of Carpathian Mountains area, from Central Europe. The analysis presented in this study follow three periods, which include 30 years climate data models of 1961-1990 (1990s), 2011-2040 (2020s), and 2041-2070 (2050s). Land cover projections forecast future changes in artificial areas, agriculture areas, and forest areas for 2020s and 2050s. For both periods (2020s and 2050s), the very low vulnerability class area is reduced while the high class appears on a large area. The worst scenario is forecasted for 2050s (high vulnerability class increase up to 2.41% of the whole study area) and is mainly due to agriculture. These findings evidence the negative impact of land cover and climate changes on the groundwater resources in the Carpathians Mountains area. The original maps carried out in this work together with the concise methodology integrated in GIS may be a useful tool for the water resources management and future strategies plans of this region. Published version

In this study, monthly time series of precipitations and temperatures from 1024 controlled and homogeneous meteorological stations located in the Emilia-Romagna region (northern Italy) are processed in order to assess potential climate changes that occurred during the period 1961–2015. Normal period as baseline between 1961 and 1990 (1990s) and recent period between 1991 and 2015 (2010s) were adopted in this study to analyse the possible effect of climate change on water availability during long-term period. Based on monthly and annual temperature (TT), precipitation (PP), and potential (ET0), the actual evapotranspiration (AET0) and water availability (WA) were computed at high spatial resolution. Between the two analysed periods, during the 2010s, it was found an increase in the maximum mean annual temperature by 1.08°C while the maximum mean annual precipitation saw a slight decrease (from 2222 mm to 2086 mm). The precipitation decrease is more intense in the South and West sectors of area (8%) and mainly depends on negative changes taking place during the winter and the beginning of spring (from December to March). The maximum mean annual ET0 and AET0 reached values of 663 mm and 565 mm during the 1990s, while during the 2010s, the found values were 668 mm and 572 mm, respectively. Because of the decrease in precipitation and increase in the ET0 and AET0, the WA (the proportion of precipitation that is available at the soil surface for subsequent infiltration and runoff processes) shows a reduction (about 10–20%) in the whole region, with exception of the North-East part of the Emilia-Romagna region. The decrease in the mean annual water availability induces severe issues concerning the water resources management across the whole Emilia-Romagna region. Published version

In the northern Apennines of Italy, springs are quite widespread over the slopes. Due to the outcropping of low-permeability geologic units, they are generally characterized by low-yield capacities and high discharge variability during the hydrologic year. In addition, low-flow periods (discharge lower than 1 Ls-1) reflect rainfall and snowmelt distribution and generally occur in summer seasons. These features strongly condition the management for water-supply purposes, making it particularly complex. The "Mulino delle Vene" springs (420 m a.s.l., Reggio Emilia Province, Italy) are one of the largest in the Apennines for mean annual discharge and dynamic storage and are considered as the main water resource in the area. They flow out from several joints and fractures at the bottom of an arenite rock mass outcrop in the vicinity of the Tresinaro River. To date, these springs have not yet been exploited, as the knowledge about the hydrogeological characteristics of the aquifer and their hydrological behaviour is not fully achieved. This study aims to describe the recharge processes and to define the hydrogeological boundaries of the aquifer. It is based on river and spring discharge monitoring and groundwater balance assessment carried out during the period 2012–2013. Results confirm the effectiveness of the approach, as it allowed the total aliquot of discharge of the springs to be assessed. Moreover, by comparing the observed discharge volume with the one calculated with the groundwater balance, the aquifer has been identified with the arenite slab (mean altitude of 580 m a.s.l.), extended about 5.5 km2 and located 1 km west of the monitored springs.

Water samples from the river network and from some shallow and brackish springs located in a tectonic window of the northern Apennines of Italy were studied in the frame of a comprehensive hydrogeological investigation in order to better understand the origin and the mixing processes between the two water types noticed also in previous studies (Ca–HCO3 and Na–Cl). A sampling campaign covering the drought period during year 2010 was planned to gather electric conductivity, temperature and redox potential data along the river network and on groundwater occurrences located inside the tectonic structure. Additionally, eight water samples were collected for hydrochemical (major anions and cations: Na+, K+, Ca2+, Mg2+, HCO3 −, Cl−, SO4 2− and trace ion Btot) and isotopic (δ18O, δ2H, 3H) analyses and compared with other eighteen samples from shallow and brackish springs collected near the study site during the period 2005–2012. Moreover, river discharge and water balance estimations were carried out. Results confirmed the presence of old Na–Cl water with salinity progressively increasing up to 5.5 g l−1 at the northern termination of the tectonic window. These values are in agreement with the ions contents of the most mineralized spring (Macognano spring: salinity of 7.6 g l−1), which has been considered as having the deepest and longest flow-path. Stable isotopes and trace ions contents are consistent with rainfall and snowmelt water mixed with brines associated with a hydrocarbon reservoir hosted at depth. Considering as end-member the more mineralized Na–Cl water, a cumulate inflow in the range of 12.9 ± 5.9 l s−1 has been estimated. This aliquot is released into the river network with different mixing proportions by the groundwater occurrences discharging from the autochthonous flysch unit.

This study discusses a dataset of water stable isotopes from precipitation (4 rain gauges) and surficial water (9 rivers) from the northern Italian Apennines, an area in which clay-rich bedrocks widely outcrop and the runoff response to precipitation events is very rapid. The dataset has been compiled starting from existing data that had previously been published in the literature and consists of monthly values of stable isotopes oxygen-18 (18O) and deuterium (2H) lasting over the period from January 2003 to December 2006 (precipitation) and from January 2006 to December 2007 (surficial water). For this period, mean residence times estimated by means of a sine-wave fitting technique make evident the significant differences over time spent by water molecules within the 9 catchments. Moreover, isotopic compositions of rivers deviated from those of precipitations revealing the influence of some catchment characteristics in differentiating the isotopic composition in rivers. Further correlations between mean residence times of river water and selected catchment characteristics reveal the role of orography and bedrocks in delaying the water molecules during their flow-paths. In addition, time series and cross&ndash, correlation analyses indicate a certain control by the main watershed divide on the isotopic composition of river waters, which is reflected in a progressive isotopic variation with longitude. The study shows that, despite using a short-time dataset (2-years for surficial water) of sparse stable isotopes can provide remarkable indications for depicting hydrological processes in large catchments made up of clay-rich bedrocks.

The Berceto landslide is a deep and active rock slide located in the northern Apennines. It affects a slope characterised by the overlapping of flysch and shale formations. The landslide has been monitored since the 1990s and an inclinometer installed in the head zone shows a sliding surface at the depth of 110 m. The landslide and the adjacent areas are affected by morphological anomalies in the slopes and in the surface drainage patterns. These anomalies are related to the presence of deep landslide or to the presence of faults in the bedrock. In particular, the River Baganza (RB) is situated at about 100 m upstream of the landslide main scarp and it is separated from the landslide by a thin layer of shale. The RB streambed is located at an elevation 70 m higher than the elevation of the active sliding surface. Due to these morphological anomalies, it is possible to speculate that the present extension of the landslide limit is not correct and that the landslide sliding surface could be extended as far as the RB. In this study, hydro-chemical and isotopic investigation have been carried out on the Berceto rock slide in order to define the lateral hydraulic boundary, the geometry of the slide surface and the groundwater flow paths. The ion contents and the δ18O-δ2H values indicate the presence in the landslide body of an external source of groundwater which could be provided by the RB through a sliding surface developed within the shale or by the flysch below the landslide body.

A new method for estimating low flows in ungauged rivers from minimum discharge of perennial springs is proposed. This spring-based approach (SBA) is tested in 21 catchments from the northern Apennines, Italy. First, the hydrogeological behaviour of each geological formation and superficial deposit is related to the spatial distribution and discharge of perennial springs in a test area using a Bayesian approach, weight of evidence (WoE). Second, the observed river flow exceeded for 95% of the observation period is related to the type of geological formations outcropping within the catchment. Finally, the q95 low flows are estimated from the WoE weights. The SBA performance is assessed by leave-one-out cross-validation and compared with the results of a multiple regression (MR) model that accounts for selected catchment characteristics, but no springs. The results show that the SBA outperforms MR. The better performance of the SBA may be related to its ability to capture bedrock characteristics, which are the main controls of low flows in the study area.

The damage and the eventual breach of river embankments may be due to internal erosion and instability processes in the waterside and landside slopes. Beside the progressive degradation of soil properties, different types of macro-pores inside the levee body can influence its short- and long-term performance. Among macro-pores, burrows are a widespread form of biologic erosion of earthen structures potentially producing damage or even their collapse. In fact, animal burrows are erosion tunnels, which can lead to piping phenomena. Thus, the emergent risk connected to burrowing animals in earthen levees has to be tackled, given also the environmental changes driven by human activity and climate. Remote sensing and geophysical surveys can complement data from in situ investigation campaigns in the definition of the real-embankment model, as well as in the imaging of local defects which may influence its local and/or global stability. Several techniques were integrated in the study area of the Panaro River, where an active animal burrow was detected in spring 2015. Two campaigns were carried out: Survey-1, in June 2015, just after the relocation of the animals, and Survey-2 in December 2015, after the filling of the burrow with a cement-bentonite slurry. Here, we highlight the peculiarity of each method and the choice of an integrated multi-technique approach. The results allowed the known burrow, as well as two other tunnels, to be imaged in 3D, providing specific guidelines for the best integrated strategy to detect and characterize these macro-pores in a fluvial levee. The proposed approach can advance our knowledge of embankments in space and time, so that effective remedial actions in flood risk and wildlife management can be identified.

This study analyses water stable isotopes data collected from precipitation (one rain gauge) and groundwater outlets (seven occurrences and two springs) at Mt. Tinisa, in the Eastern Alps of Italy. Limestones and dolostones outcrop in the mountain relief, making up a single aquifer which feeds the monitored outlets with almost steady discharges. Lack of runoff in the streambeds throughout the whole year means that all meteoric water can be considered as recharging the aquifer. Sampling was undertaken during the periods 2005–2010 (precipitation) and 2014–2015 (groundwater) via monthly and two/three-monthly field-activities, respectively, which allowed a total of 138 water samples to be gathered and analysed. Results highlighted the presence of apparent isotopic anomalies in groundwater in comparison with meteoric water. The study demonstrates that the assessment of groundwater residence time and estimates of the mean monthly isotopic content in rainwater have been necessary to correctly compare the two isotopic datasets and relate the anomaly to the recharge time-window, occurring in the late autumn.

The recent application of hydrochemistry to unstable slopes reveals the contribution of this technique to better understand hydrological processes, water rock interaction and to outline groundwater flow paths.The aim of this short note is to present results from two years of semi-continuous monitoring (discharge, EC, temperature) of two springs (Eremo and F.Cornia spring) flowing along the SE slope of Bismantova fractured slab, in the stable and unstable portion of the slope respectively. Both springs follow the precipitation pattern with the increase of discharge and decrease of temperature as consequence of rainfall recharge; moreover the increase of EC seems to suggest interaction beetween groundwater and mineral phases hosted along fractures of the slab. Using chemical results a first inverse modeling with PHREEQC have been performed in order to identify the interaction between water infiltrating in host-rock and mineral phases, as well to reconstruct geochemical evolution of groundwater from the upward stable portion to the downward unstable portion of the slope.

In large areas of the Italian Northern Apennines, hundreds of low-yield springs provide water for drinking and industrial purposes, with short groundwater flow paths being formed within fractured sedimentary rock units. This hydrogeological setting results in spring water discharges that closely follow meteoric water recharge patterns, leading to low-flow periods concentrated in the summer/early autumn. Therefore, the springs' outflow can be very sensitive to a shortage in water recharge, as it was the case in 2003 and 2017, when a prolonged period of drought caused severe water management issues. This work analyses how a group of such springs responds to climate change. In particular, we first validated a hydrological rainfall-runoff model on the basis of daily discharge data collected between 2013 and 2016. Then, outflows were simulated for baseline (1984–2013) and future periods (2021–2050) using weather data provided by five RCM-GCM combinations. Finally, we performed statistical analyses aiming to examine the intra-annual variability in discharge rates, low-flow indices, flow-duration curves and the length of low-flows. Results show no evidence of change in mean annual discharges, but future climate estimates suggest a slight change to seasonal discharges in the future, with a marked increase of discharge during winter and spring, and a decrease in summer and autumn. Q(95) and 7Q10 low-flow indices (i.e. the daily discharge exceeded 95% of the time and the minimum weekly discharge associated with a 10-year recurrence interval, respectively) are significantly affected by the climate change (− 21.8% and − 25.0%, respectively), while droughts are expected to be more frequent: the number of years with a consecutive low-flow between 51 and 100 days to increase by a third, and between 101 and 150 to duplicate.

Statistical and deterministic methods are widely used in geographic information system based landslide susceptibility mapping. This paper compares the predictive capability of three different models, namely the Weight of Evidence, the Fuzzy Logic and SHALSTAB, for producing shallow earth slide susceptibility maps, to be included as informative layers in land use planning at a local level. The test site is an area of about 450 km2 in the northern Apennines of Italy where, in April 2004, rainfall combined with snowmelt triggered hundreds of shallow earth slides that damaged roads and other infrastructure. An inventory of the landslides triggered by the event was obtained from interpretation of aerial photos dating back to May 2004. The pre-existence of mapped landslides was then checked using earlier aerial photo coverage. All the predictive models were run on the same set of geo-environmental causal factors: soil type, soil thickness, land cover, possibility of deep drainage through the bedrock, slope angle, and upslope contributing area. Model performance was assessed using a threshold-independent approach (the ROC plot). Results show that global accuracy is as high as 0.77 for both statistical models, while it is only 0.56 for SHALSTAB. Besides the limited quality of input data over large areas, the relatively poorer performance of the deterministic model maybe also due to the simplified assumptions behind the hydrological component (steady-state slope parallel flow), which can be considered unsuitable for describing the hydrologic behavior of clay slopes, that are widespread in the study area.

none 10 si Landslides of the lateral spreading type, involving brittle geological units overlying ductile terrains, are a common occurrence in the sandstone and limestone plateaux of the northern Apennines of Italy. The edges of these plateaux are often the location of rapid landslide phenomena, such as rock slides, rock falls and topples. In this paper, we present a back analysis of a recent landslide (February 2014), involving the north-eastern sector of the San Leo rock slab (northern Apennines, Emilia-Romagna Region) which is a representative example of this type of phenomena. The aquifer hosted in the fractured slab, due to its relatively higher secondary permeability in comparison to the lower clayey units leads to the development of perennial and ephemeral springs at the contact between the two units. The related piping erosion phenomena, together with slope processes in the clay-shales have led to the progressive undermining of the slab, eventually predisposing large-scale landslides. Stability analyses were conducted coupling terrestrial laser scanning (TLS) and distinct element methods (DEMs). TLS point clouds were analysed to determine the pre- and post-failure geometry, the extension of the detachment area and the joint network characteristics. The block dimensions in the landslide deposit were mapped and used to infer the spacing of the discontinuities for insertion into the numerical model. Three-dimensional distinct element simulations were conducted, with and without undermining of the rock slab. The analyses allowed an assessment of the role of the undermining, together with the presence of an almost vertical joint set, striking sub-parallel to the cliff orientation, on the development of the slope instability processes. Based on the TLS and on the numerical simulation results, an interpretation of the landslide mechanism is proposed. Spreafico, Margherita Cecilia; Francioni, Mirko; Cervi, Federico; Stead, Doug; Bitelli, Gabriele; Ghirotti, Monica; Girelli, Valentina Alena; Lucente, Claudio Corrado; Tini, Maria Alessandra; Borgatti, Lisa Spreafico, Margherita Cecilia; Francioni, Mirko; Cervi, Federico; Stead, Doug; Bitelli, Gabriele; Ghirotti, Monica; Girelli, Valentina Alena; Lucente, Claudio Corrado; Tini, Maria Alessandra; Borgatti, Lisa

The San Leo village, located near to Rimini (northern Italy), was built in the medieval period on the top of a calcarenite and sandstone plateau, affected by lateral spreading associated with secondary rock falls and topples. In fact, a number of landslides endangered the historical town since centuries. In order to describe the structural features driving these slope instability phenomena, a complete Terrestrial Laser Scanner (TLS) survey all around the San Leo cliff was performed. Moreover, Close-Range Photogrammetric (CRP) surveys and conventional geomechanical surveys on scanlines have been carried out. The 3D geometry of the cliffs was extracted and critical areas have been investigated in detail using dense Digital Surface Models (DSMs) obtained from CRP or TLS. The results were used to define the structural features of the plateau, to recognize more fractured areas, and to perform kinematic analyses, in order to assess the joint sets predisposing to slope instability at the cliff scale. The creation of a 3D model was also fundamental for the implementation of the geological model to be used in numerical modelling for hydrogeological characterization and slope stability analyses.

12 springs from the northern Apennines of Italy were studied by means of a comprehensive hydrogeological investigation to unravel recharge processes taking place in a highly fractured slab of flysch rock hosting the corresponding aquifers. Several campaigns were carried out during the period 2005–2008 to gather springs’ discharge together with electrical conductivity and temperature data. Water samples were collected and allowed the determination of the major ions (Ca2+, Mg2+, Na+, K+, SO4 2−, HCO3 −, Cl−) and the isotopic content (δ18O). Additionally, groundwater discharge from 3 selected springs was measured continuously using pressure-transducers. Over the same period, reference δ18O values for rainfall and snow-melt water were collected monthly by a rain-gauge. Results highlighted an aquifer-like behavior of this slab of flysch rock. The springs are characterized by a Ca–HCO3 hydro-facies and an increase of groundwater mineralization has been noticed moving toward the base of the slab; the mean discharges are between 0.3 and 0.7 l·s−1 and suffered a marked variability during the year; the total maximum yield is about 155,000 m3 while the total discharge volume is around 320,000 m3·y−1. By processing the δ18O isotope values from springs (mean annual values ranged from −9.67 and −10.42 ‰) and by combining them with rainfalls datasets, results show that the main aliquot of recharge occurs in the winter—spring months and it is principally related to the solid precipitations (snow-melt).

In many geological contexts, the hydrogeological features of highly fractured rock slabs can drive slope instability processes. This is the case of San Leo (northern Apennines of Italy), where groundwater processes were recognized as predisposing factor for the last large-scale rock fall that took place the 27th of February 2014. In the present work, the hydrogeological features of the San Leo slab were analyzed by means of spring-discharge analysis, piezometric monitoring data and slug tests. The maximum spring yield, the depletion coefficient and the hydraulic conductivity values were estimated. Time-series analyses were used to better understand the groundwater behavior within the rock slab and to estimate its response to rainfall regime. Moreover, the calculation of the groundwater flow direction and modulus in the unsaturated zone was performed. Results highlight the presence of two systems, which are probably related to the characteristics of different joint sets (aperture, spacing); the hydraulic conductivity values were shown to vary with depth. A first general interpretation of the aquifer behavior is given, which is related to the main structural elements of the slab.

The unsaturated zone largely controls groundwater recharge by buffering precipitation while at the same time providing preferential flow paths for infiltration. The importance of preferential flow on landslide hydrology is recognised in the literature; however, its monitoring and quantification remain difficult. This paper presents a combined hydrological and hydrochemical analysis of small-scale sprinkling experiments. It aims at showing the potential of such experiments for studying the spatial differences in dominant hydrological processes within a landslide. This methodology was tested in the highly heterogeneous black marls of the Super-Sauze landslide. The tests were performed in three areas characterised by different displacement rates, surface morphology and local hydrological conditions. Special attention was paid to testing the potential of small-scale sprinkling experiments for identifying and characterising preferential flow patterns and dominant hydrological processes.

Rapid assessment of landslide activity is important in case of adverse climatic conditions leading to civil protection’s alerts that require increased surveillance of risk areas. GB-InSAR is nowadays becoming a consolidated near-sensing monitoring technique for slope movements. It can be installed rapidly and it can rapidly provide results in the form of displacement maps. However, it has never been thoroughly tested in radar-hostile conditions such as these posed by large-scale earth slides – earth flows covered by a canopy of trees bushes and meadows, that are the typical landslides in Emilia Romagna Apennine. As sparse small villages, buildings, roads and other lifelines are often built on these landslide bodies, they are of particular concern for civil protection, especially during prolonged rainfall periods that determine attention/alerting conditions. To test the possibility to achieve improved surveillance capability in case of attention needed, a series of GB-InSAR spot campaigns lasting from a week to a month, was carried out in 2010–11 in several landslides of Emilia Romagna Apennine using a commercial interferometric radar. The aim was to evaluate the performance of the technique for rapid assessment of landslide activity, even in case of partly vegetated soil coverage conditions. The paper deals with the results obtained in 3 out of the 11 monitored sites.

Changes in soil water content, groundwater flow and a rise in pore water pressure are well-known causal or triggering factors for hillslope instability. Rainfall and snowmelt are generally assumed as the main sources of groundwater recharge. This assumption neglects the role of deep water inflow in highly tectonized areas, a factor that can influence long-term pore-pressure regimes and play a role on local slope instability. This paper aims to assess the origin of groundwater in the Ca' Lita landslide (northern Italian Apennines) and to qualify and quantify the aliquot attributable to deep water inflow. The research is essentially based on in situ monitoring and hydrochemical analyses. It involved 5 yr of continuous monitoring of groundwater levels, electrical conductivity and temperature and with groundwater sampling followed by determination of major ions (Na+, K+, Mg2+, Ca2+, Cl−, HCO3−, SO42−), tracers (such as Btot and Sr2+), and isotopes (δ18O, δ2H and 3H). Leaching experiments on soil samples, hydrochemical modelling and water recharge estimation were also carried out. Results show that the groundwater balance in the Ca' Lita landslide must take into account an inflow of deep and highly mineralised Na-SO4 water (more than 9500 μS cm−1) with non-negligible amounts of Cl− (up to 800 mg l−1). The chemical and isotopic fingerprint of this water points to oilfield water hosted at large depths in the Apennine chain and that uprises through a regional fault line crossing the landslide area. It recharges the aquifer hosted in the bedrock underlying the sliding surface (at a rate of about 49 000–85 700 m3 yr−1) and it also partly recharges the landslide body. In both the aquifers, the hydrochemical imprint of deep water mixed with rainfall and snowmelt water was observed. This indicates a probable influence of deep water inflow on the mobility of the Ca' Lita landslide, a finding that could be applicable to other large landslides occurring in highly tectonized areas in the northern Apennines or in other mountain chains. The paper demonstrates that hydrochemistry should, therefore, be considered as a valuable investigation method to define hydrogeological limits and the groundwater sources in hillslope and to assess groundwater flow patterns in deep-seated landslides.

In the northern Apennines, four representative large and deep seated landslides affecting weak rock masses have been studied before, during and after reactivation events. Semi-continuous and continuous monitoring in the 2004–2006 period included the dormancy, reactivation and suspension phases, allowing some comments to be put forward as regards the hydro-mechanical conditions that drive the reactivations. The data have highlighted the interactions between groundwater and displacement rates in different sections of the slope.

Locations of potential groundwater springs were mapped in an area of 68 km 2 in the Northern Apennines of Italy based on Weight of Evidence (WofE) and Radial Basis Function Link Net (RBFLN). A map of more than 200 springs and maps of five causal factors were uploaded to ArcGIS with Spatial Data Modelling extensions. The WofE and RBFLN potential groundwater spring maps had similar prediction rates, allowing about 50% of the training and validation springs to be predicted in about 15 to 20% of the study area. The two maps were merged using a heuristic combination matrix in order to produce two hybrid maps: one representing susceptible areas in both the WofE and RBFLN maps (type A), while the other representing susceptible areas at least in one of the two maps (type B). For small cumulated areas, the success rate of both hybrid maps was higher than that of the parent maps, while for large cumulated areas, only the type B hybrid map performed similarly to the parent maps. This conclusion suggests different applications of these maps to water management purposes.

Thermal infrared imaging technique is widely used in hydrological research for different purposes: detection of groundwater inflow into stream or sea; estimation of soil moisture, characterization of vegetation type, etc. In this study a ground-based thermal imaging camera FLIR P620 is used to identify low-thermal groundwater in- flow in creek in a mountain region. The test area is located in northern Apennines of Italy. Due to the geological history and the current geological setting of the mountain chain, it is relatively common to find thermal springs, which are characterized by anomalously high salinity and temperature. The latter, it is due to the depth of the groundwater circuits. Many of these springs were already known during Roman times when they were used for curative purposes and the surrounding areas were a source of hydrocarbons (they are often associated with methane and oil natural spills). Normally the thermal springs are located in fault zones. In some cases they are located along the slope or in other cases, they are located directly at the bottom of creeks and interfere with streams. The locations of the thermal springs have different impact for different aspects. For the archaeology could be important to find new area of research; for hydrology could be important to study base flow and water quality; for biology and ecology could be important to study different aquatic ecosystem; for engineering could be important to find new energy resources for local communities. The aim of the study was to localize thermal springs that inflow into a creek inside the Gova tectonic window (Upper Secchia river basin) which is characterized by a canyon morphology and by the outcropping of faulted and fractured sandstones that are bounded by clay formations. The mean altitude of the test site is 800 m a.s.l. The mean annual temperature is 8C and the total amount of rainfall is 1,300 mm. The normal springs are characterized by water with mean temperature around 8C and electrical conductivity from 100 to 1000 S/cm. The thermal springs are characterized by water with mean temperature of 20C and electrical conductivity from 10,000 to 20,000 S/cm. Two field surveys were realized in summer 2010 and in winter 2011. These two periods were selected because coincident with the low flow periods of the creek. Due to the high difference in temperature, between the groundwater and the water of the creek, that is around 15 degree, the winter season was the most favourable time to detect the thermal springs. During the surveys more than 10 thermal springs were detected inflow at the bottom of creeks. They generally inflow into the creek as a discrete point of discharge or, in some cases, as a diffuse seepage. In two cases, where the discharge of the springs were higher, thermal plumes with the length of some meters could be identified in the water of the creek.

The hydrogeological characteristics of roto-translational slides in flysch are complex, due to the inherent anisotropy and heterogeneity of rock masses and related deposits. The paper deals with the hydrogeological characterization of a reactivated roto-translational slide affecting Cretaceous flysch rocks, located in the northern Apennines of Italy. Continuous monitoring of groundwater levels, in-situ permeability and pumping tests, hydrochemical and physical analyses and Uranine tracers were the adopted prospecting methods. In this research hydrological monitoring and investigation are summarized in order to define a hydrogeological conceptual model of the landslide source area. Results showed that two overlaying hydrogeological units exist at the slope scale: the first is unconfined, but highly compartmentalized, and hosted in the fractured and dismembered rock slide body. The second is confined and lays in the undisturbed flysch below the sliding surface. The groundwater level in the confined hydrogeological unit is twenty meters higher than the groundwater level in the uppermost one. Moreover, the groundwater chemistry characterization revealed a rising of deep fluids in the landslide area.

This study is part of a wider feasibility analysis of a new forestry road in the Dolomitic region. The investigated area is located in northeastern Italy, in the Carnic Alps complex geological context. The rock mass which would be crossed by the tunnel is a highly tectonized limestone characterized by a relatively high strength of the intact rock. The project focuses on the rock mass characterization and the modelling of its behavior by means of numerical simulations with a Finite Elements (FE) code. The generalized Hoek-Brown criterion is used, normal and shear stiffness of the joints are evaluated and different strategies for the representation of the rock mass discontinuities are adopted. The effects of two support systems, preliminary designed by a diffused simplified method, are evaluated focusing on the space around the tunnel, where the joints reach the critical state.

Changes in soil water content, water flows and consequent rise in pore water pressure, are wellknown factors of hillslope instability. Sub surface flow conditions are considered as the main triggering factor for initiation and reactivation of landslides and rainfall is generally assumed as the only water source for groundwater recharge in shallow hillslope aquifers. In some cases, as in highly tectonized areas, faults can affect the groundwater circulation path controlling the rising of deep fluids to the ground surface. Normally, deep fluids have a chemical composition completely different from the shallow groundwater depending on the travel depth, temperature and pressure conditions, mineral composition of the rocks crossed and time of interaction. In this last case, the deep water inflow at the slip surface may at least locally influence long-term pore-pressure fluctuations, playing a role on slope stability. In several landslides located in northern Apennines of Italy (Ca Lita, Vedriano) and South Alps of French (Draix, Super-Sauze) the presence of deep fluids has been detected using hydrochemical investigations. The groundwater was sampled during several field campaigns uniformly spread out over the year from a network of boreholes. Physical and chemical analyses comprised determination of temperature, conductibility, pH, main cations and anions (K+, Na+, Cl-, Ca2+, Mg2+, SO42- and HCO-) while isotopic analysis (Oxygen, Deuterium, Strontium) are still ongoing. Water chemistry and geochemical/mineralogical analyses of the soil material have been used inside a geochemical program (Phreeqc version 2.17) to check how suitable was observed water chemistry with the reservoir characteristics. The model simulates the rock alteration by the dissolution of the primary minerals and the precipitation of new phases. Initial parameters were obtained from geochemical and mineralogical analyses or from the literature (kinetics constants). The simulations showed that for some elements (pH, sulphate and calcium), concentrations we found in groundwater could be reproduced. However, the observed high concentrations in sodium and magnesium were not correctly simulated. Furthermore, a particular anomaly in the Na+ concentration was observed in the most active part of the landslides. These results, which will be compared with the isotope analysis, led us to conclude that groundwater was locally recharged with saline waters from areas outside the watershed, coming up through the bedrock using major discontinuities.

To understand the origin of instability and the evolution of large and deep earth slide-flows, it is important to define the origin and path of groundwater and the role of the groundwater on the landslide deposit rheology. To achieve these goals it is important characterize, physically and chemically, the bedrock and slope deposits and the groundwater system. This study deals with the hydrological and geochemical characterization of a reactivated earth slide-flow affecting Cretaceous flysch, located in the northern Apennines of Italy. In situ permeability and pumping test, continuous monitoring of groundwater levels, electrical conductivity, temperature, furthermore, hydrochemical and isotope analysis were the adopted prospecting methods. In detail, oxygen, deuterium and tritium isotopes, the major cations and anions and the Boron content have been analyzed. To investigate the relation between the groundwater chemical elements, the total dissolved solids and the changing in the landslide behavior some geotechnical tests have been conducted. Groundwater levels were monitored for more than 5 years by means of transducers in 5 standpipe piezometers, fissured above or below the sliding surface. Results showed that two overlaying aquifers exist at the slope scale: an unconfined one, in the fractured flysch of the rock slide; a semi-confined one, in the undisturbed flysch below sliding surface. Pore pressure in the unconfined aquifer is controlled by rainfall, with fluctuation of several meters occurring hours or days from onset of precipitation. On the contrary, pore pressure in the semi-confined aquifer shows little response to precipitation events, has fluctuations of few meters related to seasonal trends, and maintains pressure head higher than that in the unconfined one. This makes it a relevant factor for the stability of the slide. Storage coefficient of 10-3 and hydraulic transmissivity of 1E-5 m2/s were estimated for the unconfined aquifer with a pumping test carried out with several control piezometers. The geochemical characterization obtained by sampling and lab analysis highlighted two groundwater types in the landslide area. One shallow, directly connected with rainfall, that can be classified as cold (13 C) and Cacarbonate rich with electric conductivity around 800 S/cm and which is characterized by 6.5 Unit Tritium. The second consists of deep-fluids, rich in Na-sulfate and Boron. This deep-fluids are characterized by cold temperature (13 C) and high salinity, over 4000S/cm and which is characterized by 3.5 Unit Tritium. Both groundwater have an oxygen and deuterium composition similar to the local rainfall. The results obtained in Ca’ Lita show a high complexity of the groundwater flow due to high heterogeneity and anisotropy of the hydraulic characteristics inside the landslide deposit and in the underlying fractured bedrock. Moreover, the hydrogeological study has individuated a rising of deep fluids in the landslide area, which can have a negative effect on the stability of the whole slope. The research results will be used to design and implement deep drainage systems for risk mitigation purposes.

The presence of deep faults can affect the groundwater circulation. They can control the rising of deep fluids to the ground surface. Normally, deep fluids have a chemical composition completely different from the shallow groundwater; depending on the travel depth, temperature and pressure conditions, mineral composition of the rocks crossed and time of interaction. This can affect the hydro-chemical characteristics of near-surface groundwater. Eventually, it can change the fingerprint of groundwater circulating in landslides and it can influence long-term pore-pressure fluctuations, playing a role on slope stability. In the northern Apennines of Italy, several large-scale earth slides – earth flows affecting faulted clayey formations are believed to be somehow influenced by deep fluids. The study was aimed at detecting hydro-chemical anomalies in groundwater circulating in 3 landslides that have resumed activity several times in the last decades, and that are occurring in areas of potential deep-fluid influence (Silla, Ca’ Lita, Vedriano). More than 30 water-samples were collected at different depth in the landslide body and in the underlying bedrock, owing to the presence of several piezometers. Physical and chemical analyses comprised determination of temperature, conductibility, pH, main cations and anions (K+, Na+, Cl, Ca2+, Mg2+, SO42 and HCO). Isotopic analyses (oxygen and deuterium) are still ongoing. Results allowed discriminating between a Ca-Carbonate hydrotype (400-600 µS/cm), that is interpreted as being directly connected with rainfall infiltration, and a Na-sulfate-rich hydrotype, that is interpreted as the evidence of deep fluids upflow. This would actually be the result of the mixing between two extreme hydrotypes: Na-bicarbonate water and Ca-sulfate waters, both characterized by high salinity, over 4000 µS/cm. The first is typical of geothermal water in the Apennines and is linked to the infiltration at great depth of rain water and the subsequent long term interaction between water and rock masses that allows to degradation of the Na-silicate. The second hydrotype, Ca-sulfate water, might be related to the presence of gypsum deposits in the stratigraphic sequence of the Apennines chain.

A large and morphologically spectacular rock slope instability is detected in the northern Apennines of Italy. Ten of metres of blocks and columns, in calcareous rock formation, slide and spread on clay shale, dipping down slope 30°. The geological structures and the morphological features of the slope deformation have been identified with use of high-resolution digital elevation models obtained from ground based laser scanner and airborne LiDAR. The actual morphological setting of the slope is characterized, also far away form the main scarp, by some metres high columns in vertical position. This suggests that the main deformations are parallel to the slope. Inside the landslide, rock falls are also frequent, due to the failure of large blocks and columns through set of joints. The origin of the instability is probably related with the erosion of the clay formation, at the foot of the slope, by the close torrent. From the analysis of aero-photographs of the past fifty years is possible identified an enlargement of the mass instability in the up slope direction. A destructive event was recognized in the Seventies, when the road and the bridge below the landslide were destroyed. During the event was documented the passage between slow to very fast moving. In the summer 2009, after the increase of the slope deformations of the last years, a continuous monitor system was installed. The system is a robotic station that every two hours measures 20 benchmarks fixed in the rock blocks and columns in the landslide area. Today, tens centimetre of displacements are recorded. The data show an increase of the deformations rate with the distance from the main scarp. At the moment, the evolution of the slope is controlled by continuous creeping processes and by period with accelerates deformations. These last correlate with wet and snow melt periods, which are responsible of the variation in the groundwater regime and of the changes in the material behaviour within the sliding zone

High-Resolution Digital Elevation Models (HR DEMs) obtained with Light Detection and Ranging technology, (LiDAR) have proved to be useful in the analysis of landslide processes in mountainous terrains, for different purposes and at different spatial scales, including improvement of landslide inventories, susceptibility assessment and appraisal of landslide geomorphic features. The application of laser scanning techniques results in data sets with enormous data size, extremely high accuracy (up to cm-scale) and very high spatial resolution. The exploitation of HR DEMs in landslide analysis can be manifold, comprising automated spatial data processing as well as expert knowledge - supervised procedures. First goal of this paper is to stress the advantages given by the usage of Shaded Relief datasets obtained from HR DEMs in geomorphological mapping of complex landslides. Through the use of such datasets, surveyors gain an enhanced capacity to identify slope-scale geomorpho-dynamic units, the possibility to increase the precision of scarps and detachment areas zonation, the capacity to identify and map compressive and extensional features all across the landslide body, and the possibility to retrieve other relevant geomorphological indicators of movement. These advantages are exemplified by presenting maps of large-scale earth slide – earth flows and deep seated rock slides located in the Alps and in the Apennines, that have been obtained by making use of shaded relief maps calculated from regional and local datasets using different scene illumination parameters. Second goal of this paper is to exemplify the usage of Differential HR DEMs is mass-wasting analysis applied to active earth slides - earth flows located in the northern Apennines. This simple DEM subtraction procedure can be carried out using multi-temporal airborne or terrestrial surveys, or by fusing airborne and terrestrial data. Examples are presented of landslides for which mass wasting at the slope scale and total volumetric magnitude of the events have been assessed using both single-type and fused-type data sources. Disregard possible uncertainties, these pieces of information helped in depicting possible future scenarios. Moreover, considering that earth slides – earth flows moving at a rate up to 10 m/day are difficult to be monitored with classical in situ instrumentation, the results suggest that LiDAR systems could also be used, under certain organizational conditions (temporal resolution of the surveys, costs, post-processing efforts etc.), as a near-real time monitoring system during and after reactivation events.